The Gastroenterology/Hepatology Core (Core F) oversees all gastrointestinal (GI) diagnostic, therapeutic and research activities of this Program Project. In particular, the core provides uniform assessment of GI complications, participates in protocol design by defining inclusion and exclusion criteria as well as GI endpoints, and assists in the collection and distribution of clinical specimens. Through their activities, the members of Core F contribute to the research of all Projects in this Program Project and to the quality of care provided to our patients.